1. Field of the Invention
The present invention is related to a circuit breaker, and more particularly to a circuit breaker, which can cut out the circuit with its lever being held when the circuit is under over-current.
2. Description of Related Art
When a circuit is under over-current, a circuit breaker is used to cut out the circuit for protecting the electrical equipment.
As shown on FIGS. 6 and 7, a conventional circuit breaker has a housing (80). A lever (81) is pivotally mounted on the upper end of the housing (80). A first terminal (82) and a second terminal (83) are disposed in the lower portion of the housing (80). The first terminal (82) integrally forms a bimetal (84) on the distal end within the housing (80). The bimetal (84) and the second terminal (83) respectively form two opposite platinum nodes (830), (840) in their distal ends. The bimetal (84) is connected with a linkage (85). The other end of the linkage (85) is connected to the lever (81). A U-like elastic leaf (86) is provided between the linkage (85) and the side wall of the housing (80).
FIG. 7 shows a use state of the circuit breaker. The lever (81) is pressed to drive the linkage (85) and the bimetal (84) downwards. Therefore, the platinum node (840) of the bimetal (84) is in contact with the platinum node (830) of the second terminal (83), so the circuit is conductive.
When the circuit is under over-current, the bimetal (84) is deformed as its temperature raised. Thereby, the bimetal (84), cooperated with the U-like elastic leaf (86), will be disconnected with the second terminal (83). The circuit is then cut out.
However, if the lever (81) is held by some heavy substance covering thereon, the bimetal (84) will not disconnect with the second terminal (83). In this case, the circuit breaker is failure. Then, the over-current will destroy the electrical equipment and cause a fire or other accidents.
A circuit breaker in accordance with the present invention tends to mitigate and/or obviate the aforementioned problem.